221212110 has 64 divisors (see below), whose sum is σ = 608850432. Its totient is φ = 50388096.

The previous prime is 221212099. The next prime is 221212111. The reversal of 221212110 is 11212122.

It is a super-2 number, since 2×221212110² = 97869595221304200, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212111) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64909 + ... + 68231.

It is an arithmetic number, because the mean of its divisors is an integer number (9513288).

Almost surely, 2^221212110 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221212110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (304425216).

221212110 is an abundant number, since it is smaller than the sum of its proper divisors (387638322).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221212110 is a wasteful number, since it uses less digits than its factorization.

221212110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3657.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 221212110 is about 14873.2010676922. The cubic root of 221212110 is about 604.7877223527.

Adding to 221212110 its sum of digits (12), we get a palindrome (221212122).

Adding to 221212110 its reverse (11212122), we get a palindrome (232424232).

The spelling of 221212110 in words is "two hundred twenty-one million, two hundred twelve thousand, one hundred ten".